5 Replies Latest reply: Jan 12, 2008 7:46 AM by Anonymous Brian
triplexone Level 1 Level 1 (0 points)
First post here

I got a problem with the keyboard backlit of my 15 MBP. It worked fine before: being off in the daytime and in the evening with the lamp on in my room, and lighted up when I turned off my lamp. But now, it always lights up even the lamp is on. I'm sure there is nothing covered the sensor under the speakers. It doesn't light up in the daytime. Seems the threshold of lighting up the backlit has been changed. I got the problem once before and the problem was disappeared after I re-installed Tiger, I don't know why. Now I suffer this again after I upgraded my OS to Leopard. The keyboard backlit works good in Windows installed with Boot Camp, so I think the hardware is fine and there must be some configuration changed by some way.

Does anyone know how I can solve this problem, or if there is any software can change the threshold of the backlit, or should I reset something?

Thank you very much in advance.

Macbook Pro, Mac OS X (10.5)
  • iVmichael Level 6 Level 6 (13,725 points)
    1. Try doing a Parameter RAM reset - hold down apple/option/p/r keys at start up and wait for three chimes before releasing the keys.

    2. Google for a utility called Lab Tick that allows you to set the backlight level whatever the ambient light is.
  • triplexone Level 1 Level 1 (0 points)
    Thank you very much for your replay.

    I did the PR reset once before but no help. And I know the software LabTick but it is for forcing the backlit lighting up in the daytime. My situation is that in my room with the lamp on in the evening, it still light up automatically and I can close it with F8 key. I think the lamp is bright enough to see my keyboard clearly which means I didn't need the backlit in this situation. It worked fine before, get problem now.

    Any one knows if there are some hidden parameters to fix it? I'll appreciate it.
  • Alex Repty Level 1 Level 1 (30 points)
    You can still use Lab Tick and use it to force the keyboard backlight to stay off. Just drag the slider in Lab Tick down completely (or press the appropriate hotkey if you have set one) and check the box in the preferences to keep Mac OS X from adjusting the illumination on its own. Leave Lab Tick running and you're good.

    Hope that helps,
  • triplexone Level 1 Level 1 (0 points)
    Thank you very much. Lab Tick does can force the backlit from lighting up. So can the F8 key.
  • Anonymous Brian Level 1 Level 1 (5 points)
    I was frustrated with the lack of control over the keyboard backlight, so I hacked together a simple command-line utility that can set the Macbook Pro's (and the Powerbook G4's) keyboard backlight to an arbitrary level.

    Of course, one can use this utility to manually adjust the backlight level of the keyboard, but it can be invoked programatically (e.g. in shell-scripts) as well. I have found that it is particularly useful as a "silent alarm." The following mini-script, for example, causes the keyboard backlight to flash on and off every second, which is surprisingly noticeable:

    while true; do
    backlight 1.0; sleep 1
    backlight 0.0; sleep 1

    Well, anyway, you get the idea. If anyone else has a nerdy desire to fiddle with their keyboard backlight using the command-line, I have posted my utility here:


    The zip file contains only the source code, so you will need the Apple Development Tools to compile. Let me know if you experience any problems,

    - Brian